Flexible holder sheets are known such as Ozeki, U.S. Pat. No. 4,533,048 and others. However, these are cumbersome to load, allow introduction of dust or moisture, and may allow inadvertent dislodgement of the contents.
The present invention provides pockets with shallow side walls so that the material above the walls acts as a flap and in cooperation with a like oppositely functioning flap from above can function advantageously as a loading guide, a dust and moisture guard, and a security flap.